Acid degradation of flavonoids as an aid in their identification

In the course of previous studies of constituents from Larix needles, small quantities of flavonol glycosides were hydrolysed according to standard procedures in ethanolic or aqueous HCl. In many cases, especially when very low concentrations were used, partial or complete degradation of the aglycone occurred, even when the time of hydrolysis was restricted to 5 min. Autoxidation of flavonols under acid conditions, leading to a benzoic acid, phloroglucinol (phloroglucinol carboxylic acid) and carbon monoxide, has been described. The rate of autoxidation in 1 N HCl at 1OO ° given, however, is much lower than that found in our experiments, This is probably due to the concentration used; higher concentrations of the flavonol glycosides produced under similar conditions a reasonable yield of the aglycone

Improved amine spray reagent for the detection of sugars

In the course of our investigations on naturally occurring flavonoid glycosides, the sugars obtained after acid hydrolysis were mainly analysed by gas-liquid chromatography and/or paper chromatography, using p-anisidine phosphate as the spray reagent. Often only very small amounts of the isolated compounds are available, in which case the flavonoid aglycone, possible degradation products and sugars resulting from the acid hydrolysis are analysed by paper chromatography on the same sheet. Flavonoids are detected by, e.g., measuring their UV fluorescence, which can be intensified by spraying with diphenylboric acid-ethanolamine ester (flavone reagent), and the sugars can subsequently be detected by overspraying with p-anisidine phosphate followed by heating at 100-120°

Die invloed van verskillende pelle energie en proteïen in die rantsoen op dragtige Karakoelooie en die pelse van hul pasgebore lammers

No Abstrac

Involvement of phenol metabolism in resistance of Dianthus caryophyllus to Fusarium oxysporum f.sp. dianthi

Three carnation cultivars were investigated for the effect of stem inoculation with Fusarium oxysporum f.sp. dianthi on production of phenolic compounds and on fungistatic activity. Carnation stems were characterized by a complex mixture of cell wall-bound phenolics, several of which occurred in considerable amounts. Only very low amounts of phenolic compound were present in the vacuoles. Infection with F. oxysporum f.sp. dianthi induced the production and accumulation of a number of new compounds, both free in the cell sap and bound to the cell wall. In addition, the stem extracts acquired germination-inhibiting properties for conidia of the fungus. The accumulation of several phenolics and the fungistatic activity were roughly correlated to the degree of resistance of the three cultivars. Part of the differences in their resistance to F. oxysporum f.sp. dianthi might be due to an inhibition of the conversion of phenolic acid-type precursors into phytoalexins in the more susceptible cultivars

Correlations between Accumulation of Dianthramides, Dianthalexin and Unknown Compounds, and Partial Resistance to Fusarium oxysporum f. sp. dianthi in Eleven Carnation Cultivars

The accumulation of dianthramides, dianthalexin and other phenolic compounds in carnation cells at different times before and after inoculation of plants with Fusarium oxysporum f. sp. dianthi, and the development of wilt symptoms were compared for eleven carnation cultivars. Untreated and water‐treated controls contained only a little acetone‐extractable phenolics. Upon inoculation with F. oxysporum f. sp dianthi, all cultivars accumulated the same range of phenolic compounds, including several dianthramides and dianthalexin, but in different proportions. The total amount of accumulated phenolic compounds per fresh material weight of the extracted stem segments could not be related to the disease resistance level of the different cultivars. However, the accumulation of dianthramides and dianthalexin in the cultivars was positively correlated to resistance, while the accumulation of two other, as yet unidentified, compounds was inversely related to resistance

Chemical relationship between Pinaceae

Fingerprints of phenolic compounds of leaf extracts of eleven pine species have been made by paper chromatography and HPLC. The results suggest a chemical relationship which agrees fairly well with those based on immunological and morphological characters but not always with the classification commonly used